Chain saw sharpener



Nov. l2, 1946. A. R. LoFsTRAND, JR l2,410,828

CHAIN SAW SHARPENERl Filed Nov. 19, 1943 4 Sheets-Sheet 1 iiliil, f

llzllllll' IIZIII l Lm J o/si'an N0V- l2, 1946. A. R. LoFsTRANb, JR

CHAIN SAW SHARPENER -4 "sheets-smeetv 2 Filed NOV. 19, 1943 NOV- l2, 1946- A. R. LOFSTRAND, JR 2,410,828

CHAI sAw SHARPENER Filed Nov. 19, 1943 4 Sheets-Sheet 3 Jlhhhhhh Nov. l2, 1946. A. Rl. I OFSTRAND,` JR

CHA-IN SAW SHARlAENER 4 Sheets-Sheet Filed NOV. 19, 1943 llllll .b

Patentecl Nov. 12, 1946 UNITED STATES PATENT OFFICE CHAliN SAW SHARPENER Anders R. Lofstrand, Jr., Silver Spring, Md.

Application November 19, 1943, Serial No. 510,948

Ciaims. This invention relates to a sharpening device for sharpening chain saws.

An object of this invention is to provide a chain saw lSharpener wherein the work is clamped on a vertically movable support, the support being adjustable to varying angles so that all of the teeth of the saw may be cut at the desired or proper angle. Another obj ect of this invention is to provide a chain saw Sharpener which is portable, being capable of being clamped onto any suitable sup port, and which may be operated by means lof an air motor, an electric motor, an internal combustion engine, or any suitable and available power device.

A further object of this invention is to provide a device of this kind which can be accurately set in right-angularly related planes so that the desired cutting angle may be formed on the teeth of the saw. f A further object of this invention is to provide an improved clamp for clamping the chain saw in proper position for grinding the teeth thereof. With the foregoing objects and others whichl may hereinafter appear, the invention consists of the novel construction, combination and arrangement of parts as will be more specifically referred to and illustrated in the accompanying drawings, wherein is shown an embodiment of the invention, but it is to be understood that changes, modifications and variations may be resorted to which fall within the scope of the invention as claimed.

In the drawings: Figure 1 is a detail front elevation partly in section of a chain saw Sharpener embodying this invention,

Figure 2 is a top plan partly broken away and in section of the device,

Figure 3 is a detail side elevation of the device,

Figure 4 is a detail side elevation partly in vern tical section of the device on the from that shown in Figure 3, y

Figure 5 is a fragmentary sectional View taken on the line 5 5 of Figure 1,

VVFigure 6 is a sectional View taken on the line taken side opposite l gauge or index for determining one angular position of the carriage. f

Referring to the drawings, the numeral l5 designates generally a frame structure which includes an upright frame Vmember l having formed integral with the upper end thereof Aan angularly extending table ll. A rearwardly extending stationary clamp i3 extends from the rear side of the vertical member it and an adjustable threaded clamping memberl 19 is threaded through a rearwardly extending arm 26 carried by the lower portion of the vertical frame member I6 so that the frame l5 may .be clamped onto a support S. ,I

The table or plate Il is adapted `to have secured to the upper side thereof a spindle or grinder shaft 2l. In the present instance, the grinder shaft vill is formed as part of an air motor 22 which is bolted to the upper side of the supporting plate or table Il.A Where an electric motor is used, the spindle 2l may be journaled in a bearing secured to the table l1 and the same is true where the spindle 2l is rotated by means of an internal combustion engine or other suitable power device. I

The air motor 22 includes a spring-pressed nor-'- mally closed valve 23 which is adapted to be moved into open 'position by means of a horizontally swingable lever 24 provided with a cammember 25 engageable with the valve member 23 when the lever 24 is rotated or swung in a counterclockwise direction. An abrasive wheel 2t is securedto the spindle or drive shaft 2l and the wheel 26 has mounted thereabout a guard or shield 21; The guard or shield y2l is carried'by a cylindrical clamp 23 having rearwardly extending ears 29 which are drawn together by means of a pressure bolt 29a so that the guard or shield 21 may be disposed in the proper position. VThe guard or shield 2l is positioned to expose the wheel 25 on the lower side thereof so that the teeth of Va chain saw mounted on a vertically movable carriage may be properly sharpened. The frame l5 includes a forwardly extending arm 30 at the lower end of the vertical frame membei` 16 and a cylindrical guide 3l is carried by the forward end of the arm 39. The guide 3l at the upper end thereof has formed integral therewith an annular plate 32 and the plate 32 constitutes a limit means for limiting the downward movement of a saw carriage, generally designated as 33.

The carriage 33 includes a vertically slidable shaftt which is slidable in the bore 35 of the bushing or guide 3|. An annular plate 36 is secured by means of a bolt or cap screw 31 at the upper end of the shaft 34, and preferably, the plate 36 is formed with a socket or downwardly opening recess 38 within which the upper end of the shaft 34 is adapted to engage. The shaft 34 adjacent the upper end thereof is formed with an annular groove39, and a half-circular clamping collar 40 engages in the groove 39. A pressure screw 4| is threaded in an opening, 42 provided in the plate 36 and the screw 4| is formed with a reduced inner end 43 engaging in an opening 44 formed in the central portion of the clamping 4 larly adjusted position by means of a thumb nut 69 which is threaded on a bolt 18. The bolt 10 extends through an arcuate slot 1| formed in the vertical plate 68 and a spacer sleeve 12 is intercollar 40. The screw 4| at the outer end thereof l is provided with a handle 45 so that when it is desired to rotatably adjust the plate or table 36 on the upper end of the shaft 34, the screw 4| may be loosened and the desired adjustment made sovv as to angularly position the saw in the desired angular relation with respect to the abrading whee126.

'I'he carriage 33 is adapted to Ibe manually raised to an operative position for bringing the teeth of the chain saw into engagement with the abrading wheel by means of a rock lever 46. The rock lever 46 is pivotally mounted on a pivot member 41 carried by the lower portion of the frame member I6, and the shaft 34 has extending laterally therefrom a pin 48 which is secured to the shaft 34 by means of a bolt or cap screw 49. The pin 48 as shown in Figure 8 is formed with a sleeve 58 which slidably engages in an elongated slot 5| formed in the handle or lever 46 between the ends thereof. The bushing, or guide 3| is also formed with a vertical slot 52 within which the pin 48 slidably engages so that the shaft or slide 34 will be held against rotation but will be permitted vertical sliding movement.l The shaft 34 is limited in its upward movement by means of a reduced diameter downwardly extending threaded stud 53 which is carried by the lower end of the shaft 34, and an adjustable nut 54 is threaded onto the stud 53- A lock nut 55 is also threaded on the stud 53 and is adapted to lock the adjusting nut 54 in the desired position.

A cotter pin 56 or the like is extended through a the lower portion of the stud 53 so that the two nuts 54 and 55 cannot `be unthreaded from the stud 53 during normal use of the device. The upper side of the plate 35 has secured thereto an arcuate gauge plate 51 and a pointer 58 is interposed between the Ibolt or cap screw 31'and the upper side of the plate 36, there preferably being a washer 59 between the pointer 58 and the plate 36 so that the pointer 58 will overlie the gauge member 51. l

The carriage 33 also includes an upwardly extending vertically disposed plate Y68 which is formed integral with the plate 36, The vertical plate 6D constitutes a clamp support and extends laterally from the plate 36, as shown in Figure 1. A clamping structure, generally designated as 6|, is pivotally secured on a, pivot member 62 which extends through a bushing or boss 63 carriedby the plate or support 68. The clamp structure 6| includes a pair of clamping plates 64 and 65 which are disposed in spaced relation, there being a spacer plate 66 between the plates 64 and 65 rlhe clamp structure 6|4 is'locked its anguposed between the forward side of the plate 60 and the rear side of the clamping plate 65. A pointer 13 is secured to the rear side of the clamping plate 65 and is adapted to move over an arcuate gauge plate 14 which is secured to an arcuate ange 15 carried by the plate 66 atits outer or left end. The chain saw C is formed with sprocket engaging lugs 16 which are adapted to be disposed between the two plates 64 and 65 and the links 11 of the saw are adapted to rest on the upper edges 61 and 68 of the clamping member 6|. The lugs 16 are locked between the plates 64 and 65 by means of a pressure screw 18 which extends loosely through the front plate 64 and is threaded into the rear` plate 65. The screw 18 includes an angularly disposed handle 19 by means of which the screw 18 may be tightened or loosened.

A selected tooth T of the chain saw is adapted to be disposed in the proper position'for sharpening by the wheel 26 by means of a slide structure 88 which is carried by the clamping member 6|. The slide structure 88 includes a sliding plate 8| disposed between the clamping members 64 and 65 and slidably engaging the upper edge of the spacer member 66. The two plates 64 and 65 are provided with elongated openings 82 and 83, respectively, and the slide plate 8| is also formed with a vertical slot 84. A threaded shaft is secured in outwardly or forwardly extended position with respect to the forward plate 64, being supported on a pair of forwardly extending ears 86 which are struck from the forward plate 64. A circular nut 81 is threaded on the relatively stationary shaft 85 and is adapted to engage in the slot 84 of the slide plate 8|. Movement of the nut 81 lengthwise of the shaft 85 will move the slide plate 8| between the plates 64 and 65 and lengthwise of the clamping member 6|.

The 'slide plate 8| has secured thereto a pair of upwardly extending resilient fingers 88 and 89 which are secured at their lower ends to blocks 96 and 9|, respectively, by fastening members 92. The blocks 98 and 9| are secured on opposite sides of the slide member 8| and the resilient fingers 88 and 89 extend upwardly above the clamping members 64 and 65. The finger 88 has secured to the upper end thereof and on the rear side a block 93 which is formed with an inclined'inner face 94. The upper end of the rear resilient finger 89 has secured to the upper end thereof a block 95 formed with an inclined inner side 96 and the inclined inner sides 94 and 96 are disposed in convergent relation towards the right as viewed in Figure 2.

The blocks 93 and 95 are adapted to engage the opposite sides of the chain saw C so as to hold the saw against tilting and to coact with the clamping plates 64 and 65 in firmly holding the saw in a proper position for sharpening of a selected tooth. Y

In the use and operation of this Sharpener, the frame I5 is secured to the desired support S and the motor 22 is connected to a suitable source of air pressure supply so that the wheel 26 will be rotated when the valve member 23 is moved to an open position. The chain saw C is mounted on the clamping member or structure 6| with the lugs 16 engaging betweenthe plates 64 and 65 and the links 11 of the saw resting on the upper edges of the plates 64 and 65. Theopposite ends of the plates 64 and 65 are preferably curved, as indicated at 91, so that the chain saw can depend from the clamping structure 6l, as shown in Figure 1.

The carriage 33 is angularly adjusted about the vertical aXis of the shaft 34 by loosening the clamping collar lil after which the clamping segment 4l) may be tightened so as. to firmly hold the plate 36 against movement relative to the shaft 34. The clamping structure 6l may be vertically adjusted on the horizontal pivot 62 by loosening the nut 69 and swinging the clamping structure to the desired position, as shown by the pointer 13 and the gauge 'F4'. l

Before the clamping screw i8 is tightened, the saw adjusting nut 81 is adjusted lengthwise of the shaft 85 so that the proper tooth of the saW is in the proper position for grinding ofthe cutting edge thereof. When the saw has been adjusted lengthwise of the clamping vstructure 6|, the clamping screw 18 may be tightened by the handle 'I9 so that the chain saw Will be held against movement with respect to the clamping structure 6I.

The carriage shifting handle or lever 46 may then be raised thereby bringing the selected tooth into engagement with the abrasive wheel 26. The upward limit of movement of the carriage 33 is adjusted by adjusting the limit nut 5d which is then locked by the lock nut 55. Having once made the proper adjustments of the carriage 33 and the clamping structure 6I, the desired teeth of the saw can be ground, it being understood that the chain saw C includes right and left cutting teeth and a central raker tooth so that the angular adjustment of the carriage 33 and of the clamping structure 6| will be made for the cutting teeth on one side of the saw and may be readjusted for the cutting teeth on the other side and a further adjustment made for the raker teeth.

What I claim is:

1. A chain saw Sharpener comprising a frame, a grinding wheel rotatably carried by said frame, a vertically shiftable carriage carried by said frame, a pair of saw clamping plates disposed in a vertical position, means pivotally mounting said plates on said carriage, means holding said plates in adjusted position, a pair of opposed resilient saw gripping fingers, a slide secured to said iingers and movable lengthwise of said plates, and means adjusting said slide lengthwise of said plates, including cooperating screw and adjustable nut.

2. A chain saw Sharpener comprising a frame, a grinding wheel rotatably carried by said frame, a vertically shiftable carriage carried by said frame, a pair of saw clamping plates disposed in a vertical position, means pivotally mounting said plates on said carriage, means holding said plates in adjusted position, a pair of opposed saw gripping fingers extending above said plates, and means slidably mounting said fingers for adjustment lengthwise of said plate.

3. A chain saw Sharpener comprising a frame, a grinding wheel rotatably carried by said frame, a vertically shiftable carriage carried by said frame, a pair of saw clamping plates disposed in a vertical position, means pivotally mounting said plates on said carriage, means holding said plates in adjusted position, a pair of opposed resilient saw gripping fingers, a slide secured to said fingers and movable lengthwise of said plates, and means adjusting said slide lengthwise of said plates.

4. In a chain saw Sharpener, a movable carriage, a pair of saw clamping plates carried by said carriage, a pair of opposed saw gripping fingers disposed partially above said plates, said plates being formed with elongated guide slots, a slide loosely engaging in said slots, means securing said lingers to said slide for movement therewith, means for simultaneously locking said slide and clamping said plates on opposite sides of the saw, and means for adjusting said slide lengthwise 0f said slots.

5. In a chain saw Sharpener as set forth in' claim 4 wherein said slide adjusting means includes a stationary threaded shaft carried by one of said plates, and a nut threaded on said shaft, said slide having an opening in which a portion of said nut engages whereby movement of said nut lengthwise of said shaft will shift said slide.

ANDERS R. LOFSTRAND, JR. 

